Embodiments herein relate generally to methods of preparing stabilized metal-containing nanoparticles and conductive ink compositions containing stabilized metal-containing nanoparticles prepared by such methods. Certain embodiments are drawn to methods that can result in increased yields of stabilized metal-containing nanoparticles having good dispersibility in organic solvents and suitable for use in fabrication of electronic features having high conductivity.
With the rise of the internet of things (IOT), conductive 3D printed objects can find many applications in creating smart components for automotive and rail, aerospace, military, home appliances and many other applications. These smart structures can be built by the incorporation of functional elements such as conductive tracks and electronics into 3D printed structures. This can enhance their functionality and create new higher value products. Most 3D printed structures are manufactured from polymeric materials. In order to fabricate 3D printed structural electronics, highly conductive materials that are compatible with structural materials used in 3D printing are required.
Solution processable metal-containing nanoparticles can be used to fabricate conducting features in electronic devices (such as electrodes and electrical interconnectors, among others) by low-cost solution deposition and patterning techniques. However, there have been challenges in synthesizing high quality, solution processable conducting materials (such as silver nanoparticles) on a large scale.
Additionally, most available conductive inks that employ metal-containing nanoparticles need to be annealed at very high temperatures which can lead to the melting/softening of low melting point or low glass transition temperature, polymeric structures, including those made by 3D printing methods.
Commercial nanoparticles are available. One such nanoparticle is synthesized by reducing a silver salt and then including a stabilizing binder made from dodecylamine around the resulting particles.
It would be desirable to have methods for the production of solution processable conducting materials of consistent quality that could be performed on a scale suitable for commercial manufacturing. There is also a need to develop conductive inks that anneal at lower temperature to enable fabrication of conductive objects using low temperature substrate materials, such as the materials employed in 3D printing. The ink annealing temperature depends on the nanoparticle that is used to formulate the ink.